The amino acid content of sake koji was analyzed by preparing eighty-five kinds of koji samples in separate petri dishes using five kinds of rice varieties and seventeen kinds of koji strains. The amount of amino acids formed in the sake koji making process was also estimated. Amounts of mycelia, enzyme activity, and amino acid totals of 85 koji samples were analyzed by variance, discrimination, and cluster analyses. The findings are as follows:
(1) Koji samples abundant in residual amino acids showed high enzyme activity. (2) About 80% of the amino acids formed from steamed rice were utilized by the koji mold while 20% remained in the koji. (3) The major residual amino acids of the koji were glutamine and arginine. (4) The quantity of residual amino acid in koji may be reduced by half with on optimal combination of rice variety and koji mold strain.
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